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Hi there! I'm Studyfin. Today, we are going to explore how fossils tell the amazing story of Earth's past!
Fossils are the preserved remains or traces of ancient life. They act like clues left behind, showing us what plants and animals lived millions of years ago.
Fossils form in layers of sedimentary rock. Over time, newer layers of mud and sand pile on top of older ones, trapping bones and shells beneath them.
By comparing these rock layers, we can find the relative age of fossils. The oldest fossils are found at the bottom, while the newest are near the top.
Imagine you are analyzing a cliff side. You find a fossil of a trilobite (an ancient sea creature) in the lowest layer of rock. In the top layer, you find a fossil of a mammal tooth. Explain which fossil is older and how you know.
- First, identify the locations of both fossils in the rock layers. The trilobite is at the bottom, and the mammal tooth is at the top.
- Next, apply the rule of relative dating. This rule states that older rock layers are deposited first, so they sit at the very bottom.
- Then, compare the positions. Since the trilobite is in the lowest layer, it must have been buried long before the mammal tooth.
- Finally, conclude that the trilobite fossil is the older of the two because of its deep position in the sedimentary rock layers.
